Bump NUnit3TestAdapter from 3.9.0 to 3.11.2 (#411)

Bumps [NUnit3TestAdapter](https://github.com/nunit/nunit3-vs-adapter) from 3.9.0 to 3.11.2.
- [Release notes](https://github.com/nunit/nunit3-vs-adapter/releases)
- [Commits](https://github.com/nunit/nunit3-vs-adapter/commits/3.11.2)

Signed-off-by: dependabot[bot] <support@dependabot.com>

System.IO.Abstractions.TestingHelpers.Tests/System.IO.Abstractions.TestingHelpers.Tests.csproj

@@ -47,7 +47,7 @@
 
   <ItemGroup>
     <PackageReference Include="nunit" Version="3.8.1" />
-    <PackageReference Include="NUnit3TestAdapter" Version="3.9.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="3.11.2" />
   </ItemGroup>
 
   <ItemGroup>